Geochemical evolution of a karst stream in Devils Icebox Cave, Missouri, USA

A 3.7 km flowpath along the main stream channel in Devils Icebox Cave, Boone County, Missouri, was sampled on 23 January, 23 March and 18 September 1994. In January 1994, the water was oversaturated with respect to both calcite and dolomite, and only minor compositional changes were observed along the flowpath. In March 1994, the water was oversaturated with respect to calcite but undersaturated with respect to dolomite. Using a mass-balance approach, the composition of the stream water at downstream locations was predicted by dissolution of dolomite (a maximum of 0.16 mmol s −1) and by a minor amount of calcite precipitation (a maximum of 0.03 mmol s −1). In September 1994, there were increases in the Mg, Ca, and total inorganic carbon (TIC) mass fluxes that were due to the dissolution of dolomite ( SI dolomite